Essentially, we need Africa to become more economically developed as soon as possible, and when that happens, it's almost certain that they'll follow the same trends that we've seen in happen in other developed countries: stabilizing populations and more serious efforts to protect their natural resources and environment. Unfortunately, we can only encourage these countries to protect their natural assets, but there's really nothing we can do short of that.
1. Well large land animals are an important source of tourism. Tourism is a huge source of income for many poor countries in Africa, like for example it's 12% of the GDP in Kenya. Most governments want to protect them and is willing to accept aid, it's individuals that want to poach them for personal gain. Which basically means they'll take funding, equipment, personnel, anything you're willing to give really. Granted, they'll probably not care so much about CO2 emissions or whatever. Then again, neither do Americans.
2. The reason the poachers are being so successful is because they're well funded from abroad, they're not fighting against the poor man in the street but heavy criminals propped up by first world technology. We can do a lot to try cutting off this supply, catch the smuggling, prosecuting the buyers, tear down the organizations and so on. It's organized crime, just not in a shape we see much of in the western world.